The present invention relates generally to the mixing of cementitious materials. More particularly, the present invention relates to dispensing reinforcing fibers into cementitious mixtures. Even more particularly, the present invention relates to an apparatus for more accurately and efficiently dispensing fibers into a cementitious mixture. Still more particularly, the present invention relates to an apparatus that automatically dispenses fiber quantities measured to commercial tolerances at the job site. Most particularly, the present invention relates to dispensing pre-measured quantities of fibers provided in a segmented belt.
Adding reinforcing fibers to cementitious materials and other aggregate produces desirable properties in these materials. For example, the presence of fibers may improve the ductility, toughness, and impact resistance of cementitious materials. The use of discrete fibers in the reinforcement of concrete is set forth in U.S. Pat. No. 3,645,961. The patent discloses the use of nylon, polyvinyl chloride and simple polyolefins in lengths ranging between one-quarter and three inches (0.6 to 7.5 cm).
When adding fibers at the job site, it is difficult to dispense accurate amounts of fiber into the cementitious mixture. Known field dispensing devices are portable, however, as they use weight or volumetric control, they have poor tolerances. Moreover, after production, fibers tend to agglomerate further aggravating weight or volume measurements. To overcome this problem, fibers are weighed at the manufacturing plant to commercial tolerances, and then packaged in paper bags. After transporting the bags to the job site, these bags are then tossed directly into the-concrete mixer at the job site. One U.S. patent describing this method is U.S. Pat. No. 5,224,774 and provided an improvement over the use of plastic film bags which needed to be opened, then their contents were dumped into the mixer and finally the empty bags were collected, as waste.
Manually adding the fibers is time-consuming and laborious. Manpower used for adding the fibers could be dedicated to pouring and spreading the concrete. When large amounts of fiber are added, the tedium of manually adding the fiber bags may cause workers to loose count of the number of bags added to the mix resulting in an inaccurate mixture.
As can be appreciated, the quantity of fiber dispensed in the material is critical in at least two respects. First, the quantity of fiber affects the physical characteristics of the resultant material. Second, on a per weight basis, the fibers are the most expensive component in the mixture.
Therefore, a need exists for a fiber dispensing device that dispenses fibers within commercial tolerances.
There is a further need for a fiber dispensing device that can be readily used at the job site to deliver fibers directly into concrete, measured to commercial tolerances.
There is a further need for a fiber dispensing article that can be used to continuously supply fibers in pre-measured quantities.
There is a further need for a fiber dispensing apparatus that eliminates manual delivery of the fibers to the mixer and automatically measures the quantity of fiber being added. Heretofore, the art has not provided such an apparatus. U.S. Pat. No. 1,916,531 provides an apparatus for loading cement bags into a mixer, employing a conveyor belt with buckets into which the bags of cement are placed by the operator, following which the bags are counted and emptied into the mixer.
It is therefore an object of the present invention to provide a fiber dispensing apparatus that can be used to deliver quantities of fibers measured to commercial tolerances.
It is another object of the present invention to provide a fiber dispensing apparatus that can be used to automatically tally the amount of fiber added to the mixer.
It is another object of the present invention to provide a fiber dispensing apparatus that dispenses fibers within commercial tolerances.
It is another object of the present invention to provide a continuous segmented train of individual and separate containers that encapsulate discrete quantities of fibers, measured to commercial tolerances.
It is another object of the present invention to provide a train providing a plurality of containers carrying pre-measured quantities of fibers and a plurality of webs, joining the containers together at spaced intervals.
It is another object of the present invention to provide a fiber dispensing apparatus that controls the amount of fiber added to a mixer.
It is another object of the present invention to provide a fiber dispensing apparatus having a controller that stops the flow of fibers into a mixer when sufficient fibers have been added to the mixer.
It is another object of the present invention to provide a method for conveying sealed pre-measured quantities of fibers suitable for the reinforcement of cementitious materials to a mixing apparatus therefor.
In general, the present invention provides an apparatus for transporting pre-measured quantities of fibers in a plurality of containers, separated by a plurality of webs, joining the containers together at spaced intervals, to a mixer for cementitious materials, the apparatus comprising means for conveying, the containers therethrough; a counter assembly; a web slitting assembly; and a process controller, which activates the web slitting assembly in response to input from the counter assembly, in order to sever a determined number of the containers from the webs for conveyance into the mixer.
The present invention also provides a method for conveying premeasured quantities of fibers suitable for the reinforcement of cementitious materials to a mixing apparatus therefor comprising providing a plurality of containers, each carrying a pre-measured quantity of fibers separated by a plurality of webs, joining the containers together at spaced intervals; feeding the containers through a dispensing apparatus; counting a predetermined number of the containers within the apparatus; intermittently slitting containers from the webs in response to the step of counting; and feeding the containers into the mixing apparatus.
The present invention also provides in combination, a train carrying pre-measured quantities of fibers and a dispensing apparatus for transporting the pre-measured quantities of fibers to a mixer for cementitious materials, the train comprising a plurality of containers, each carrying a premeasured quantity of fibers; and a plurality of webs, joining the containers together at spaced intervals; the apparatus comprising means for conveying the containers therethrough; a counter assembly; a web slitting assembly; and a process controller, which activates the web slitting assembly in response to input from the counter assembly, in order to sever a determined number of the containers from the train for conveyance into the mixer.
Finally, the present invention also provides a train for providing pre-measured quantities of fiber comprising a plurality of containers containing the fibers; and a plurality of webs, joining the containers together at spaced intervals.